Bought an old cellar. Does it only carry wooden studs or also solid construction?

Hello everyone, a few weeks ago we bought a plot of land on which there is a basement (built in 1989). The house on it was removed after a fire last year. Apart from the extinguishing water, the basement was not affected and is in good condition. Previously, there was a 1.5-story wooden house on it. We would preferably like to have another 1.5-story house and are currently in talks with various house providers (solid construction & lightweight construction) and were made aware by one of the solid builders that the foundation in solid construction would only support one floor (ground floor). So the attic could not be expanded. Are highly insulating pumice or Poroton bricks really that much heavier? The basement is a prefabricated basement made of reinforced concrete but consistently only 14 cm thick, with outer dimensions of 11.5m x 11.5m overall. The foundations are unreinforced strip foundations B 15, 30 x 50 cm. Concrete slab B 15 We have all the structural plans ready, but I have no idea what to look for. Before I contact any more solid builders, I would like to know if solid construction is even an option for us. Can this somehow be roughly inferred from the plans without commissioning a structural engineer directly? Best regards from the Palatinate

Hello Olli, it will not work here without a structural engineer, commenting from a distance won't help you! He is the expert who can help you and such a decision can take just an hour.

A timber frame panel house is nowadays not dramatically much lighter either, they no longer have the wall thicknesses they had thirty years ago and more.

Otherwise, basically everything is available:
- Architect plans
- Expert report describing the materials and construction method

Then show both here once.

The basement is a precast basement made of reinforced concrete, but throughout only 14 cm thick,

Given the year of construction, I find that hard to believe even under a timber house. But maybe I will see more with drawings, the pictures from your other thread are not sufficient for me.

A timber frame panel house nowadays is not dramatically much lighter either; they no longer have the wall thicknesses they did thirty years ago or more.

Then show both here.

Considering the year of construction, I find it hard to believe even for a wooden house. But maybe I'll see more with drawings; the pictures from your other thread are not enough for me.

All right, here are the plans. The wall widths on the architect's plan are not correct, but those in the structural plan are exact (measured manually).

All right, here are the plans. The walls on the architect's plan are not correct in width, but those on the structural plan are exact (measured manually).

I don't quite understand the plans, more precisely: two cellars are depicted. In the drawings where there are also plans of the ceiling fields, it looks like a concrete cellar with walls as thin as the ceilings. But the individual cellar plan from Breisgau Haus (apparently belonging to a "wooden house") and unfortunately without structural information is apparently a masonry cellar with an exterior wall thickness of 36.5 cm, which regardless of what exactly it is made of, should also support a house with the same wall thickness. Which of these two cellars was actually built? - Was the masonry cellar only offered and did the builder then change his mind in favor of a prefabricated cellar?

Yes, so if we understood correctly, the architect of Breisgau Haus originally planned a masonry basement, but a precast concrete basement was built instead – the one shown in the other plans. I have attached the Breisgau Haus plan again just so you can see how the basement is now being used. So the room layout, etc.

A builder told us that concrete can bear more load and that is probably why the masonry was swapped for thinner concrete walls in the planning back then.